Question

The equivalent conductance of Ba2+ and Cl– are respectively 127 and76 ohm-1 cm-1
eq-1 at infinite dilution. The equivalent conductance of BaCl2 at infinite dilution in the unit ohm-1 cm-1eq-1 will be
A. 139.5
B. 203
C. 279
D. 101.5

Answer 1

Answer:

A.139.5

Explanation:

Kohlrausch law:

"At infinite dilution, when dissociation is complete, each ion makes a definite contribution towards equivalent conductance of the electrolyte irrespective of the nature of the ion with which it Is associated and the value of equivalent conductance at infinite dilution for any electrolyte is the sum of the contribution of its constituent ions", i.e., anions and cations.

The chemical equation is,

BaCl

2

→Ba

2+

+2Cl

−

Λ

BaCl

2

0

=Λ

Ba

2+

0

+2Cl

−

=127+2×76=279 ohm

−1

cm

2

mol

−1

Equivalent conductivity =

2

279

=139.5 ohm

−1

cm

2

eq

−1